1. Field of the Invention
The present invention relates to computer networks and, more specifically, to configuring devices utilized in computer networks.
2. Background Information
Many organizations, including businesses, governments and educational institutions, utilize computer networks so that employees and others may share and exchange information and/or resources. A computer network typically comprises a plurality of entities interconnected by means of one or more communications media. An entity may consist of any device, such as a computer, that “sources” (i.e., transmits) or “sinks” (i.e., receives) data frames over the communications media. A common type of computer network is a local area network (“LAN”) which typically refers to a privately owned network within a single building or campus. LANs typically employ a data communication protocol (LAN standard), such as Ethernet, that defines the functions performed by data link and physical layers of a communications architecture (i.e., a protocol stack).
One or more intermediate network devices are often used to couple LANs together and allow the corresponding entities to exchange information. For example, a bridge may be used to provide a “bridging” or “switching” function between two or more LANs or end stations. Typically, the bridge is a computer and includes a plurality of ports that may be coupled to end stations, other bridges, routers or other network entities. The bridge includes one or more line cards and/or network interface cards (NICs) that establish ports for the exchange of network messages. Ports used to couple bridges to each other are generally referred to as a trunk ports, whereas ports used to couple bridges to end stations are generally referred to as access ports. The bridging function includes receiving data from a sending entity at a source port and transferring that data to at least one destination port for forwarding to one or more receiving entities.
Switches may also be classified depending on the role they play within the computer network. An access switch, for example, refers to an intermediate network device to which end stations, e.g., workstations, servers, etc., are directly coupled, and which is typically located at an edge of a computer network. A distribution switch refers to an intermediate network device to which one or more access switches are directly coupled. Distribution switches are often deployed in a central portion of the network.
Typically, the ports of a switch are physically connected, e.g., by cables, to the end stations, switches, routers, etc. After the ports of the switch have been connected as desired, a network administrator configures the switch in order to set operating conditions and to specify the protocols and applications that are to run on the interfaces corresponding to the switch ports. An interface refers to the boundary between protocol layers of a communication stack, such as the boundary between the physical and data link layers or between the data link and Internet Protocol (IP) layers. Thus, each port of a switch has one or more interfaces associated with it, and the terms interface and port are used interchangeably throughout this document. To configure the interfaces of a bridge, the network administrator enters a series of commands at the Command Line Interface (CLI) of a management console, and conveys those commands to the bridge. Each of the bridge's interfaces has a corresponding name or identity, such as a number. Typically, the interface number is assigned by the factory when the respective line card or NIC is installed into the switch. A command, such as “show interfaces”, when entered at the management console will return a report listing all of the interfaces on the bridge and their corresponding numbers. Examples of interface identifiers include “Serial 0”, “Ethernet 2”, etc.
To begin configuring a given interface, the network administrator enters a command at the CLI specifying the given interface, such as “interface ethernet 2”. The network administrator then enters a series of commands. For example, to set the size of a transmit queue at the interface, the network administrator may enter the command “tx-queue-limit number”. To adjust the maximum packet size, the network administrator may enter the command “mtu bytes”. After entering all of the desired configuration commands, the network administrator exits the configuration process. The configuration commands are then collected, executed and applied to the specified interface. The configuration is thereafter fixed to that interface, i.e., to “interface ethernet 2”. Once an interface has been configured, the network administrator can review the command sequence by entering a “show” type command.
Network administrators typically configure the interfaces of a bridge differently depending on what device is to be connected to the interface. For example, suppose interface “Ethernet 2” is connected to a combination desktop PC/Voice over Internet Protocol (VoIP) phone, while interface “FastEthernet 7” is connected to a backbone router. The network administrator may configure an Access Control List (ACL) on the “Fast Ethernet 7” interface that blocks certain types of un-wanted traffic from being sent and/or received on that interface. The network administrator may also configure each interface with one or more Port Virtual Local Area Network IDs. If the device is a router, the network administrator configures each interface with one or more IP addresses.
The process of configuring interfaces, as described above, is time-consuming for network administrators. It is also error prone, especially when changes are made to the network. Suppose, for example, that a combined desktop PC/VoIP phone, which had been connected to interface “Ethernet 2”, is moved to a new port corresponding to interface “Ethernet 15”, and that a distribution switch is connected to the port corresponding to interface “Ethernet 2”. In this case, the network administrator must go in and configure the “Ethernet 15” interface. He or she must also change the configuration of interface “Ethernet 2”. This often requires that the network administrator be logged into the switch, e.g., by a laptop computer, or be in voice contact with someone at the management console, e.g., by phone, as the physical cabling is being changed.
As more and more changes are made the network, it is possible that interfaces may become mis-configured, since the device actually coupled to a given interface may be very different from the one for which the interface was originally configured. Such errors, moreover, can be difficult to discover. These types of mis-configurations may result in reduced performance of the computer network. They may also result in improper access being granted to different parts of the network, thereby compromising the network's security. Accordingly, a need exists to simplify the process of configuring interfaces, and to reduce the errors that can result from changes or modifications to the network.